Melamine and masonite for 2 six-slot racks: $200
Heat tape, thermostats, metal foil tape, wiring: $175
My time (at my regular wage) 12 hours x $20: $240
Total: $615 (!!!)
and all I got was 2 six-slot racks that weigh a ton; I have the experience and know-how, but I still would have been better off buying some!
Here are the pics: